• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.2
• /
• pp.199-208
• /
• 2003

Continuously variable transmission (CVT) mechanisms considered here combine the functions of a K-H-V type differential gear unit and a V-belt type continuously variable unit (CVU). As combining the functions of a K-H-V type differential gear unit and a V-belt type CVU, 24 different mechanisms are presented. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. These mechanisms have many advantages which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral.

• The tire
• /
• s.246
• /
• pp.10-19
• /
• 2011

일본 대지진으로 인해 세계 경제의 불확실성이 높아가고 있는 가운데 최근 자동차 부품수출이 급증하면서 자동차 부품 산업이 새로운 성장동력 산업으로 부상하고 있다. 우리나라의 타이어 수출은 타이어업체의 해외 생산 확대에도 불구하고 증가하고 있으나, 국내 산업 분류상 타이어가 자동차부품으로 분류되지 않음으로써 관심을 끌지 못하고 있다. 국내 타이어산업은 지속적인 연구개발 투자에 힘입어 혁신역량을 강화하면서 글로벌산업으로 성장하였으며, 세계 시장 점유율을 확대하고 있다. 본고에서는 국내 자동차 부품산업의 수출 현황과 환경 변화 및 국내외 자동차 부품업체의 혁신 전략에 대해 살펴 본 후 불확실성시대의 국내 타이어산업의 혁신 역량 강화 전략을 제시해 보기로 한다.

• Proceedings of the Korea Contents Association Conference
• /
• 2010.05a
• /
• pp.121-125
• /
• 2010

최근 온라인게임, e-Book, 모바일콘텐츠, 포털 등 IT 기반의 새로운 서비스 산업으로서 디지털콘텐츠 산업이 급성장하고 있다. 또한, 과거 엔터테인먼트 위주의 콘텐츠산업이 미래에는 제조, 서비스를 포함한 전 산업영역에 체화융합되어 확산되고, CT 및 IT 기반의 새로운 콘텐츠 산업이 급성장할 것으로 전망되는 등 융합형 콘텐츠에 대한 관심이 증대되고 있다. 정부에서도 신성장동력으로서의 융합형 콘텐츠 산업에 주목하여, 관련 산업을 발굴육성하는데 정책적 관심을 기울이고 있다. 기존의 콘텐츠 분류체계는 영화, 음악, 방송 등 장르 중심적이어서 관련 기술의 발전 및 융합현상을 제대로 반영하지 못하는 한계점을 가지고 있다. 따라서 미래 정책추진의 기반(base)로서 효과적으로 활용되고, 콘텐츠 분야의 외연확장을 포괄하는 새로운 분류체계(taxonomy)의 정립이 요구되는 상황이다. 이에 본 고에서는 미래 정책추진 및 산업활성화에 초점을 맞추어 기존 분류체계의 한계점을 극복하는 차세대 융합형 콘텐츠 산업에 대한 새로운 분류체계를 제시하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.05a
• /
• pp.302-305
• /
• 2019

국민 청원 사이트가 뛰어난 접근성과 신속성으로 인하여 국민들로부터 많은 관심을 받고 있다. 현재 국민청원 사이트의 카테고리 분류는 '미래', '성장동력' 등을 포함한 16개의 카테고리 및 기타로 구성되어 있으나 그 기준이 모호하여 많은 청원글들이 기타 카테고리로 분류되고 있는 상황이다. 이는 청원글의 내용을 명확히 반영하지 않고 미리 정의된 카테고리 구조를 사용하고 있는데서 기인한다고 할 수 있다. 본 논문에서는 보다 구체적으로 정의된 카테고리를 정의하고자 추천 순으로 1,500개의 청원글을 수집하였고, 수집된 청원글의 내용을 바탕으로 카테고리 구조를 추출하였다. 먼저, k-평균 알고리즘을 적용하여 청원글을 군집하여 대분류를 정의하였고, 보다 구체적인 세부 분류를 정의하기 위하여 토픽모델링을 실시하였다. 본 논문에서 제시하는 계층적 카테고리 구조는 청원글의 내용을 바탕으로 대분류와 세부분류로 구성된 것이므로 새로운 청원글을 등록하거나 분류하는 데 적절한 것으로 보인다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.6
• /
• pp.662-669
• /
• 2018

Recently, the installation of submarine power cables is under consideration due to the increase of electric power usage and the development of the offshore wind farm in island areas, including Jeju. In order to protect power cables installed on the seabed, it is necessary to calculate the burial depth based on the characteristics of anchoring, dragging and fishing, etc. However, there is no design standard related to the size of target ships to protect the cables in Korea. In this study, we analyzed the design standards for the protection of domestic submarine pipelines similar to submarine cables, and developed the risk matrix based on the classification by emergency anchoring considering the installation environment, then designed the size of target ships according to the cumulative function scale by ship size sailing through the sea concerned. Also, we linked marine accident conditions, such as anchoring, dragging, etc. and the environmental conditions such as current, sea-area depth of installation etc. to the criteria of the protection of submarine cable, and examined the size of specific target ships by dividing the operating environment of ships into harbor, coastal and short sea. To confirm the adequacy and availability of the size of target ships, we verified this result by applying to No. 3 submarine power cables, which is to be installed in the section from Wando to Jeju Island. This result is expected to influence in the development of a protection system for submarine cables and pipelines as well as the selection of anchor weight according to the determination of burial depth.

• Journal of the KSME
• /
• v.28 no.2
• /
• pp.150-155
• /
• 1988

공학의 기본을 이루고 있는 Newton의 역할은 고체역학과 유체역학으로 분류가 되며 고체역학은 다시 정역학과 동역학으로 세분된다. 동역학은 가속의 운동을 가진 물체를 다루는 학문으로 다시 두 부분으로 나누어진다. 하나는 운동학(kinematics)이고 다른 하나는 운동역학(kinetics) 이다. 운동학은 운동자체 즉 속도, 가속도만을 취급하며 운동역학은 운동을 일으키는 힘과 그 결과로 생기는 운동을 연관짓는 학문이다.

• Journal of Power System Engineering
• /
• v.7 no.2
• /
• pp.29-35
• /
• 2003

The monitoring and diagnostics of the rotating machinery have been received considerable attention for many years. The objectives are to classify the machinery condition and to find out the cause of abnormal condition. This paper describes a classification method of diagnosing the small reciprocating compressor for refrigerators using the artificial neural network and the wavelet transform. In order to extract salient features, the wavelet transform are used from primary noise signals. Since the wavelet transform decomposes raw time-waveform signals into two respective parts in the time space and frequency domain, more and better features can be obtained easier than time-waveform analysis. In the training phase for classification, self-organizing feature map(SOFM) and learning vector quantization(LVQ) are applied, and the accuracies of them ate compared with each other. This paper is focused on the development of an advanced signal classifier to automatize the vibration signal pattern recognition. This method is verified by small reciprocating compressors, for refrigerator and normal and abnormal conditions are classified with high flexibility and reliability.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.3
• /
• pp.128-133
• /
• 2018

Korean civil airworthiness requirements of powerplant system are regulated by KAS(Korean Airworthiness Standard) Part 23 and Part 33. These are equivalent to FAR Part 23, Part 33 of FAA, and CS-23 and CS-E of EASA. FAA and EASA rewrite the airworthiness requirements for small airplane. They changed current 'prescriptive regulation' to a 'performance-based regulation' which makes safety performance the objective. Powerplant requirements have also been changed extensively by this concept revolution. In accordance with this reorganization, we studied the new powerplant system requirements of FAR Part 23 and proposed ideal directions to rewrite the Korean Airworthiness Standard.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.3
• /
• pp.181-189
• /
• 2015

Powered prosthesis is used to assist walking of people with an amputated lower limb and/or weak leg strength. The accurate gait phase classification is indispensable in smooth movement control of the powered prosthesis. In previous gait phase classification using physical sensors, there is limitation that powered prosthesis should be simulated as same as the speed of training process. Therefore, we propose EMG signal based gait phase recognition method to classify stairs ascending and stairs descending into four steps without using physical sensors, respectively. RMS, VAR, MAV, SSC, ZC, WAMP features are extracted from EMG signal data and LDA(Linear Discriminant Analysis) classifier is used. In the training process, the AHRS sensor produces various ranges of walking steps according to the change of knee angles. The experimental results show that the average accuracies of the proposed method are about 85.6% in stairs ascending and 69.5% in stairs descending whereas those of preliminary studies are about 58.5% in stairs ascending and 35.3% in stairs descending. In addition, we can analyze the average recognition ratio of each gait step with respect to the individual muscle.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.1
• /
• pp.67-72
• /
• 2017

This study developed an electric power propulsion personal watercraft by combining a battery and an electric system from the domestic automobile industry with water motorcycle from marine leisure industry in a convergence of technology. It also developed a safety inspection plan and type approval standard for personal watercraft that use electric power propulsion. For the registration and production of the electric power PWC (Personal Watercraft), a safety inspection standard (draft) and type approval standard (draft) have been established. PWC that use this electric power propulsion certification standard have been divided into two categories according to the use of gasoline engines as related to the ship's electrical system. The contents of these safety inspections standards is divided into 7 categories, and their purpose is to confirm the facilities used for the safe operation of PWC. Type approval is divided into 7 categories and is intended to ensure the safe production of PWC. This is basic data can be used to establish criteria for safety inspection and type approval of electric power propulsion vessels and to guide the production of the environmentally friendly PWC in Korea.